Use of calcium sulfate in an inorganic mortar system based on aluminous cement to increase load values

ABSTRACT

An inorganic mortar system for a chemical fastening of an anchor in a mineral surface includes calcium sulfate, a component A, and a component B for initiating a curing process. Component A includes water, aluminous cement, at least one plasticizer, and at least one blocking agent selected from phosphoric acid, metaphosphoric acid, phosphorous acid, and a phosphonic acid. Component B includes an initiator, at least one retarder, at least one mineral filler, and water. Component A is also a curable composition.

This application is a National Stage entry under § 371 of InternationalApplication No. PCT/EP2016/075022, filed on Oct. 19, 2016, and whichclaims the benefit of the following European Patent Applications: i)15190509.8, filed on Oct. 20, 2015; ii) 15190508.0, filed on Oct. 20,2015; and iii) 15190503.1, filed on Oct. 20, 2015.

FIELD OF THE INVENTION

The present invention pertains to a use of calcium sulfate in aninorganic mortar system for a chemical fastening of anchoring means inmineral surfaces, comprising a curable aluminous cement component A andan initiator component B for initiating the curing process, component Afurther comprising at least one blocking agent selected from the groupconsisting of phosphoric acid, metaphosphoric acid, phosphorous acid andphosphonic acids, at least one plasticizer and water, and component Bcomprising an initiator, at least one retarder, at least one mineralfiller and water. In particular, the present invention pertains to theuse of calcium sulfate in an inorganic mortar system for a chemicalfastening of anchoring means in mineral surfaces to increase load valuesas well as to reduce shrinkage. Moreover, the present invention pertainsto a method for a chemical fastening of anchoring means, preferably ofmetal elements, in mineral surfaces, such as structures made ofbrickwork, concrete, pervious concrete or natural stone.

BACKGROUND OF THE INVENTION

Many mortar systems exist which provide a good chemical fastening ofanchoring means in mineral surfaces. For example, organic systems basedon free-radically polymerizable resins are used when fast curing isdesired. However, such systems are generally known to be polluting,expensive, potentially hazardous and/or toxic for the environment andfor the person who handles them and they often need to be specificallylabelled. Moreover, organic systems often show a much reduced stabilitywhen thermally exposed to strong sunlight or otherwise elevatedtemperatures, such as fire, thereby decreasing their mechanicalperformance when it comes to chemically fastening of anchoring means.

In order to overcome these drawbacks, predominantly mineral systemsbased on aluminous cement have been developed. Aluminous cement has asits major constituent monocalcium aluminate and is widely used in thebuilding and construction industries as the final products evidence ahigh level of mechanical performance over extended periods of time.Also, aluminous cement is resistant to bases and attains its maximumstrength more rapidly than Portland cement and is capable ofwithstanding solutions of sulfates. Hence, aluminous cement systems arepreferably employed in the field of chemical anchoring.

When it comes to chemically fastening anchoring means in mineralsurfaces, most of the known systems lack sufficient fluidity for mostpractical applications of the resultant compositions. Often such priorart compositions also evidence a tendency to crack in a relatively shorttime or do not exhibit the required mechanical performance, inparticular under certain conditions such as under the influence ofelevated temperatures, in diamond-drilled boreholes, or in wet boreholesas well as over a long period of time. Moreover, known systems tend toexhibit a large extend of shrinkage when applied in a borehole whichresults in an insufficient anchoring of the anchoring means.

Therefore, there is a need for an inorganic mortar system, preferably atwo-component inorganic mortar system, which is superior over the priorart systems. In particular, it is of interest to provide a system thatcan be used for a chemical fastening of anchoring means in mineralsurfaces without adversely affecting the handling, characteristics andthe mechanical performance of the chemical anchoring system, especiallywhen applied in diamond-drilled boreholes, in wet boreholes and over along period of time. Especially, there is a need for a system thatprovides increased load values when compared to the known systems. Inaddition, there is a long felt need to compensate shrinkage of themortar in the borehole to secure anchoring of the anchoring means, suchas anchor rods, threaded anchor rods, bolts or steel reinforcement bars.

In view of the above, it is an object of the present invention toprovide an inorganic mortar system, preferably a multiple-componentmortar system, in particular a two-component inorganic mortar system,which has an excellent mechanical performance, in particular undercertain conditions such as in diamond-drilled boreholes, in wetboreholes and over a long period of time and at the same time havingincreased load values when compared to the known systems. Further, theinorganic mortar system should exhibit low shrinkage to guarantee secureanchoring application.

Moreover, it is an object of the present invention to provide a methodfor a chemical fastening of anchoring means, preferably of metalelements, in mineral surfaces, such as structures made of brickwork,concrete, pervious concrete or natural stone.

These and other objectives as they will become apparent from theensuring description of the invention are solved by the presentinvention as described in the independent claims. The dependent claimspertain to preferred embodiments.

SUMMARY OF THE INVENTION

In one aspect, the present invention pertains to a use of calciumsulfate in an inorganic mortar system for a chemical fastening ofanchoring means in mineral surfaces, comprising a curable aluminouscement component A and an initiator component B for initiating thecuring process, component A further comprising at least one blockingagent selected from the group consisting of phosphoric acid,metaphosphoric acid, phosphorous acid and phosphonic acids, at least oneplasticizer and water, and component B comprising an initiator, at leastone retarder, at least one mineral filler and water.

In another aspect, the present invention pertains to a use of calciumsulfate in an inorganic mortar system for a chemical fastening ofanchoring means in mineral surfaces to increase load values.

In yet another aspect, the present invention pertains to a use ofcalcium sulfate in an inorganic mortar system for a chemical fasteningof anchoring means in mineral surfaces to reduce shrinkage.

Finally, in another aspect, the present invention pertains to a methodfor a chemical fastening of anchoring means, preferably of metalelements, in mineral surfaces, such as structures made of brickwork,concrete, pervious concrete or natural stone.

DETAILED DESCRIPTION OF THE INVENTION

The following terms and definitions will be used in the context of thepresent invention:

As used in the context of present invention, the singular forms of “a”and “an” also include the respective plurals unless the context clearlydictates otherwise. Thus, the term “a” or “an” is intended to mean “oneor more” or “at least one”, unless indicated otherwise.

The term “aluminous cement” in the context of the present inventionrefers to a calcium aluminate cement that consists predominantly ofhydraulic active calcium aluminates. Alternative names are “high-aluminacement” or “Ciment fondu” in French. The main active constituent ofcalcium aluminate cements is monocalcium aluminate (CaAl₂O₄, CaO.Al₂O₃,or CA in the cement chemist notation).

The term “initiator” in the context of the present invention refers to acompound or composition that modifies the chemical environment to starta particular chemical reaction. In the present invention the initiatormodifies the pH-value of the mortar suspension thereby de-blocking thehydraulic binder in the final mixture.

The term “retarder” in the context of the present invention refers to acompound or composition that modifies the chemical environment to delaya particular chemical reaction. In the present invention the retardermodifies the hydration ability of the calcium aluminate cement of themortar suspension thereby delaying the hydraulic binder action in thefinal mixture.

The term “initial set-time” in the context of the present inventionrefers to the time at which the mixture of component A and component Bstarts to set after mixing. During the time period after mixing, themixture stays in the form of a more or less fluid aqueous suspension orpaste of solid products.

It has been surprisingly found out by the inventors, that the additionof a calcium sulfate to an inorganic mortar system for a chemicalfastening of anchoring means in mineral surfaces, comprising a curablealuminous cement component, preferably based on calcium aluminatecement, results in a significant increase of load values when comparedto a system not comprising calcium sulfate. Moreover, the addition ofcalcium sulfate reduces shrinkage to a significant extend therebyguaranteeing secure anchoring application. It has also been found outthat the addition of calcium aluminate does not adversely affecting thehandling, characteristics and the mechanical performance of the chemicalanchoring system, especially when applied in diamond-drilled boreholes,in wet boreholes and over a long period of time.

In particular, it has been found out, that the ratio of calcium sulfateto the aluminous cement component plays an important role in theincrease of load values as well in the application of the inorganicmortar system in diamond-drilled boreholes and in wet boreholes.

Therefore, the present invention pertains to a use of calcium sulfate inan inorganic mortar system for a chemical fastening of anchoring meansin mineral surfaces, comprising a curable aluminous cement component Aand an initiator component B in for initiating the curing process. Inparticular, component A further comprises at least one blocking agentselected from the group consisting of phosphoric acid, metaphosphoricacid, phosphorous acid and phosphonic acids, at least one plasticizerand water, and component B comprises an initiator, at least oneretarder, at least one mineral filler and water.

Component A as used in the present invention is based on an aluminouscement (CA) or a calcium sulfoaluminate cement (CAS). The aluminouscement component which can be used in the present invention ispreferably an aluminous cement component based on an aqueous-phasecalcium aluminate cement (CAC). The aluminous cement to be used in thepresent invention is characterized by rapid set and rapid hardening,rapid drying, excellent resistance to corrosion and shrinkage. Such acalcium aluminate cement suitable to be used in the present invention isfor example Ternal® White (Kerneos, France).

It has been found that if component A comprises a mixture of calciumaluminate cement (CAC) and calcium sulfate (CaSO₄), rapid ettringiteformation takes place during hydration. In concrete chemistryhexacalcium aluminate trisulfate hydrate, represented by the generalformula (CaO)₆(Al₂O₃)(SO₃)₃.32H₂O or (CaO)₃(Al₂O₃)(CaSO₄)₃.32H₂O, isformed by the reaction of calcium aluminate with calcium sulfate,resulting in quick setting and hardening as well as in shrinkagecompensation or even expansion.

The calcium sulfate used in an inorganic mortar system for a chemicalfastening of anchoring means in mineral surfaces according to thepresent invention, is in the form of calcium sulfate anhydrite, calciumsulfate hemihydrate or calcium sulfate dihydrate. In a preferredembodiment of the present invention the calcium sulfate used is in theform of calcium sulfate hemihydrate.

The calcium sulfate used according to the present invention, iscomprised in the curable aluminous cement component A of the inorganicmortar system. In a preferred embodiment of the present invention, thecalcium sulfate is comprised in a curable aluminous cement componentbased on an aqueous-phase calcium aluminate cement of the inorganicmortar system.

In particular, the calcium sulfate comprised in the curable aluminouscement component A is present in a ratio of calcium sulfate to aluminouscement in a range of from 5/95 to 30/70, preferably from 15/85 to 25/75,most preferably in a ratio of 15/85. In a particular preferredembodiment of the present invention, the calcium sulfate is present inthe curable aluminous cement component based on an aqueous-phase calciumaluminate cement in a ratio of calcium sulfate to calcium aluminatecement in a range of from 5/95 to 30/70, preferably from 15/85 to 25/75,most preferably in a ratio of 15/85. In a most preferred embodiment ofthe present invention, calcium sulfate hemihydrate is present in thecurable aluminous cement component based on an aqueous-phase calciumaluminate cement in a ratio of calcium sulfate hemihydrate to calciumaluminate cement in a range of from 5/95 to 30/70, preferably from 15/85to 25/75, most preferably in a ratio of 15/85.

Component A as used in the present invention comprises at least about 40wt.-%, preferably at least about 50 wt.-%, more preferably at leastabout 60 wt.-%, most preferably at least about 65 wt.-%, from about 40wt.-% to about 80 wt.-%, preferably from about 50 wt.-% to about 80wt.-%, more preferably from about 60 wt.-% to about 75 wt.-%, mostpreferably from about 65 wt.-% to about 70 wt.-% of aluminous cement,preferably calcium aluminate cement, based on the total weight ofcomponent A.

In a preferred embodiment, component A comprises at least about 53wt.-%, more preferably at least about 58 wt.-%, most preferably at leastabout 65 wt.-%, from about 53 wt.-% to about 74 wt.-%, preferably fromabout 58 wt.-% to about 70 wt.-%, more preferably from about 63 wt.-% toabout 68 wt.-%, most preferably from about 64 wt.-% to about 77 wt.-% ofcalcium aluminate cement, based on the total weight of component A andat least about 3 wt.-%, preferably at least about 15 wt.-%, morepreferably at least about 10 wt.-%, most preferably at least about 15wt.-%, from about 3 wt.-% to about 25 wt.-%, preferably from about 4wt.-% to about 30 wt.-%, more preferably from about 6 wt.-% to about 20wt.-%, most preferably from about 10 wt.-% to about 15 wt.-% of calciumsulfate, preferably calcium sulfate hemihydrate, based on the totalweight of component A. In a most preferred embodiment, component Acomprises about 65 wt.-% of calcium aluminate cement and about 11 wt.-%calcium sulfate, preferably calcium sulfate hemihydrate, based on thetotal weight of component A.

The blocking agent comprised in component A as used in the presentinvention is selected from the group consisting of phosphoric acid,metaphosphoric acid, phosphorous acid and phosphonic acids, preferablyis phosphoric acid or metaphosphoric acid, most preferably is phosphoricacid, in particular an 85% aqueous solution of phosphoric acid.Component A comprises at least about 0.1 wt.-%, preferably at leastabout 0.3 wt.-%, more preferably at least about 0.4 wt.-%, mostpreferably at least about 0.5 wt.-%, from about 0.1 wt.-% to about 20wt.-%, preferably from about 0.1 wt.-% to about 15 wt.-%, morepreferably from about 0.1 wt.-% to about 10 wt.-%, most preferably fromabout 0.3 wt.-% to about 10 wt.-% of said blocking agent, based on thetotal weight of component A. In a preferred embodiment, component Acomprises from about 0.3 wt.-% to about 10 wt.-% of 85% aqueous solutionof phosphoric acid, based on the total weight of component A.Preferably, the amounts of aluminous cement and/or calciumsulfoaluminate cement by weight relative to the hydraulic binder totalweight are higher than any of the following values: 50%, 60%, 70%, 80%,90%, 95%, 99% or are 100%.

The plasticizer comprised in component A as used in the presentinvention is selected from the group consisting of low molecular weight(LMW) polyacrylic acid polymers, superplasticizers from the family ofpolyphosphonate polyox and polycarbonate polyox, and ethacrylsuperplasticizers from the polycarboxylate ether group, and mixturesthereof, for example Ethacryl™ G (Coatex, Arkema Group, France), Acumer™1051 (Rohm and Haas, U.K.), or Sika® ViscoCrete®-20 HE (Sika, Germany).Suitable plasticizers are commercially available products. Component Acomprises at least about 0.2 wt.-%, preferably at least about 0.3 wt.-%,more preferably at least about 0.4 wt.-%, most preferably at least about0.5 wt.-%, from about 0.2 wt.-% to about 20 wt.-%, preferably from about0.3 wt.-% to about 15 wt.-%, more preferably from about 0.4 wt.-% toabout 10 wt.-%, most preferably from about 0.5 wt.-% to about 5 wt.-% ofsaid plasticizer, based on the total weight of component A.

In an advantageous embodiment, component A further comprises thefollowing characteristics, taken alone or in combination.

Component A may additionally comprise a thickening agent. The thickeningagents which can be used in the present invention may be selected fromthe group consisting of organic products, such as xanthan gum, welan gumor DIUTAN® gum (CPKelko, USA), starched-derived ethers, guar-derivedethers, polyacrylamide, carrageenan, agar agar, and mineral products,such as clay, and their mixtures. Suitable thickening agents arecommercially available products. Component A comprises at least about0.01 wt.-%, preferably at least about 0.1 wt.-%, more preferably atleast about 0.2 wt.-%, most preferably at least about 0.3 wt.-%, fromabout 0.01 wt.-% to about 10 wt.-%, preferably from about 0.1 wt.-% toabout 5 wt.-%, more preferably from about 0.2 wt.-% to about 1 wt.-%,most preferably from about 0.3 wt.-% to about 0.7 wt.-% of saidthickening agent, based on the total weight of component A.

Component A may further comprise an antibacterial or biocidal agent. Theantibacterial or biocidal agents which can be used in the presentinvention may be selected from the group consisting of compounds of theisothiazolinone family, such as methylisothiazolinone (MIT),octylisothiazolinone (OIT) and benzoisothiazolinone (BIT) and theirmixtures. Suitable antibacterial or biocidal agents are commerciallyavailable products. Exemplarily mentioned are Ecocide K35R (Progiven,France) and Nuosept OB 03 (Ashland, The Netherlands). Component Acomprises at least about 0.001 wt.-%, preferably at least about 0.005wt.-%, more preferably at least about 0.01 wt.-%, most preferably atleast about 0.015 wt.-%, from about 0.001 wt.-% to about 1.5 wt.-%,preferably from about 0.005 wt.-% to about 0.1 wt.-%, more preferablyfrom about 0.01 wt.-% to about 0.075 wt.-%, most preferably from about0.015 wt.-% to about 0.03 wt.-% of said antibacterial or biocidal agent,based on the total weight of component A. In a preferred embodiment,component A comprises from about 0.015 wt.-% to about 0.03 wt.-% ofNuosept OB 03, based on the total weight of component A.

In an alternative embodiment, component A comprises at least one filler,in particular an organic or mineral filler. The filler which can be usedin the present invention may be selected from the group consisting ofquartz powder, preferably quartz powder having an averaged grain size(d50%) of about 16 μm, quartz sand, clay, fly ash, fumed silica,carbonate compounds, pigments, titanium oxides, light fillers, and theirmixtures. Suitable mineral fillers are commercially available products.Exemplarily mentioned is quartz powder Millisil W12 or W6 (QuarzwerkeGmbH, Germany). Component A comprises at least about 1 wt.-%, preferablyat least about 2 wt.-%, more preferably at least about 5 wt.-%, mostpreferably at least about 8 wt.-%, from about 1 wt.-% to about 50 wt.-%,preferably from about 2 wt.-% to about 40 wt.-%, more preferably fromabout 5 wt.-% to about 30 wt.-%, most preferably from about 8 wt.-% toabout 20 wt.-% of said at least one filler, based on the total weight ofcomponent A.

The water content comprised in component A is at least about 1 wt.-%,preferably at least about 5 wt.-%, more preferably at least about 10wt.-%, most preferably at least about 20 wt.-%, from about 1 wt.-% toabout 50 wt.-%, preferably from about 5 wt.-% to about 40 wt.-%, morepreferably from about 10 wt.-% to about 30 wt.-%, most preferably fromabout 15 wt.-% to about 25 wt.-%, based on the total weight of componentA.

The presence of a plasticizer, thickening agent as well as anantibacterial or biocidal agent does not change the overall inorganicnature of the cementitious component A.

Component A comprising the aluminous cement or calcium sulfoaluminatecement is present in aqueous-phase, preferably in form of a slurry orpaste.

Component B as used in the present invention comprises an initiator, atleast one retarder, at least one mineral filler and water. To ensure asufficient processing time, whereby the initial-set time is at least 5min or more, at least one retarder, which prevents premature hardeningof the mortar composition, is used in a distinct concentration inaddition to the initiator component.

The initiator present in component B is comprised of an activatorcomponent and an accelerator component which comprise a mixture ofalkali and/or alkaline earth metal salts.

In particular, the activator component is constituted of at least onealkali and/or alkaline earth metal salt selected from the groupconsisting of hydroxides, chlorides, sulfates, phosphates, monohydrogenphosphates, dihydrogen phosphates, nitrates, carbonates and mixturesthereof, preferably the activator component is an alkali or alkalineearth metal salt, more preferably is a calcium metal salt, such ascalcium hydroxide, calcium sulfate, calcium carbonate or calciumphosphate, a sodium metal salt, such as sodium hydroxide, sodiumsulfate, sodium carbonate or sodium phosphate, or a lithium metal salt,such as lithium hydroxide, lithium sulfate, lithium carbonate or lithiumphosphate, most preferably is lithium hydroxide. In one preferredembodiment the lithium hydroxide used in component B is a 10% aqueoussolution of lithium hydroxide.

Component B comprises at least about 0.01 wt.-%, preferably at leastabout 0.02 wt.-%, more preferably at least about 0.05 wt.-%, mostpreferably at least about 1 wt.-%, from about 0.01 wt.-% to about 40wt.-%, preferably from about 0.02 wt.-% to about 35 wt.-%, morepreferably from about 0.05 wt.-% to about 30 wt.-%, most preferably fromabout 1 wt.-% to about 25 wt.-% of said activator, based on the totalweight of component B. In a particular preferred embodiment, theactivator is comprised of water and lithium hydroxide. The water contentcomprised in component B is at least about 1 wt.-%, preferably at leastabout 5 wt.-%, more preferably at least about 10 wt.-%, most preferablyat least about 20 wt.-%, from about 1 wt.-% to about 60 wt.-%,preferably from about 5 wt.-% to about 50 wt.-%, more preferably fromabout 10 wt.-% to about 40 wt.-%, most preferably from about 15 wt.-% toabout 30 wt.-%, based on the total weight of component B. The lithiumhydroxide content comprised in component B is at least about 0.1 wt.-%,preferably at least about 0.5 wt.-%, more preferably at least about 1.0wt.-%, most preferably at least about 1.5 wt.-%, from about 0.1 wt.-% toabout 5 wt.-%, preferably from about 0.5 wt.-% to about 4 wt.-%, morepreferably from about 1.0 wt.-% to about 3 wt.-%, most preferably fromabout 1.5 wt.-% to about 2.5 wt.-%, based on the total weight ofcomponent B. In a most preferred embodiment, component B comprises fromabout 2.0 wt.-% to about 20 wt.-% of a 10% aqueous solution of lithiumhydroxide, based on the total weight of component B.

The accelerator component is constituted of at least one alkali and/orearth alkaline metal salt selected from the group consisting ofhydroxides, chlorides, sulfates, phosphates, monohydrogen phosphates,dihydrogen phosphates, nitrates, carbonates and mixtures thereof,preferably the accelerator component is an alkali or earth alkalinemetal salt, still preferably is a water-soluble alkali or earth alkalinemetal salt, more preferably is a calcium metal salt, such as calciumhydroxide, calcium sulfate, calcium carbonate, calcium chloride, calciumformate or calcium phosphate, a sodium metal salt, such as sodiumhydroxide, sodium sulfate, sodium carbonate, sodium chloride, sodiumformate or sodium phosphate, or a lithium metal salt, such as lithiumhydroxide, lithium sulfate, lithium sulfate monohydrate, lithiumcarbonate, lithium chloride, lithium formate or lithium phosphate, mostpreferably is lithium sulfate or lithium sulfate monohydrate. ComponentB comprises at least about 0.01 wt.-%, preferably at least about 0.05wt.-%, more preferably at least about 0.1 wt.-%, most preferably atleast about 1.0 wt.-%, from about 0.01 wt.-% to about 25 wt.-%,preferably from about 0.05 wt.-% to about 20 wt.-%, more preferably fromabout 0.1 wt.-% to about 15 wt.-%, most preferably from about 1.0 wt.-%to about 10 wt.-% of said accelerator, based on the total weight ofcomponent B.

In a particular preferred embodiment of component B as used in thepresent invention, the ratio of 10% aqueous solution of lithiumhydroxide/lithium sulfate or lithium sulfate monohydrate is 7/1 or 6/1.

The at least one retarder comprised in component B as used in thepresent invention is selected from the group consisting of citric acid,tartaric acid, lactic acid, salicylic acid, gluconic acid and mixturesthereof, preferably is a mixture of citric acid and tartaric acid.Component B comprises at least about 0.1 wt.-%, preferably at leastabout 0.2 wt.-%, more preferably at least about 0.5 wt.-%, mostpreferably at least about 1.0 wt.-%, from about 0.1 wt.-% to about 25wt.-%, preferably from about 0.2 wt.-% to about 15 wt.-%, morepreferably from about 0.5 wt.-% to about 15 wt.-%, most preferably fromabout 1.0 wt.-% to about 10 wt.-% of said retarder, based on the totalweight of component B.

In a particular preferred embodiment of component B as used in thepresent invention, the ratio of citric acid/tartaric acid is 1.6/1.

The at least one mineral filler comprised in component B as used in thepresent invention is selected from the group consisting of limestonefillers, sand, crushed stones, gravels, pebbles and mixtures thereof,preferred are limestone fillers, such as various calcium carbonates. Theat least one mineral filler is preferably selected from the groupconsisting of limestone fillers or quartz fillers, such as quartz powderMillisil W12 or W6 (Quarzwerke GmbH, Germany) and quartz sand. The atleast one mineral filler of component B is most preferably a calciumcarbonate or a mixture of calcium carbonates. Component B comprises atleast about 30 wt.-%, preferably at least about 40 wt.-%, morepreferably at least about 50 wt.-%, still more preferably at least about60 wt.-%, most preferably at least about 70 wt.-%, from about 30 wt.-%to about 95 wt.-%, preferably from about 35 wt.-% to about 90 wt.-%,more preferably from about 40 wt.-% to about 85 wt.-%, still morepreferably from about 45 wt.-% to about 80 wt.-%, most preferably fromabout 50 wt.-% to about 75 wt.-% of at least one mineral filler, basedon the total weight of component B. The at least one mineral filler ischosen to obtain a particle size complementary to that of the aluminouscement.

It is preferred that the at least one mineral filler has an averageparticle size of not more than 500 μm, more preferably of not more than400 μm, most preferably not more than 350 μm.

In a particular preferred embodiment, the at least one mineral fillercomprised in component B is mixture of three different calciumcarbonates, i.e. calcium carbonate fines, such as different Omyacarb®types (Omya International AG, Germany). Most preferably, the firstcalcium carbonate has an average particle size (d50%) of about 3.2 μmand a residue of 0.05% on a 45 μm sieve (determined according to ISO787/7). The second calcium carbonate has an average particle size (d50%)of about 7.3 μm and a residue of 0.5% on a 140 μm sieve (determinedaccording to ISO 787/7). The third calcium carbonate has an averageparticle size (d50%) of about 83 μm and a residue of 1.0% on a 315 μmsieve (determined according to ISO 787/7). In a particular preferredembodiment of component B, the ratio of first calcium carbonate/secondcalcium carbonate/third calcium carbonate is 1/1.5/2 or 1/1.4/2.2.

In a particular preferred alternative embodiment, the at least onemineral filler comprised in component B is mixture of three differentquartz fillers. Most preferably, the first quartz filler is a quartzsand having an average particle size (d50%) of about 240 μm. The secondquartz filler is a quartz powder having an average grain size (d50%) ofabout 40 μm. The third quartz filler is a quartz powder having anaverage grain size (d50%) of about 15 μm. In a particular preferredembodiment of component B as used in the present invention, the ratio offirst quartz filler/second quartz filler/third quartz filler is 3/2/1.

In an advantageous embodiment, component B further comprises thefollowing characteristics, taken alone or in combination.

Component B may additionally comprise a thickening agent. The thickeningagent to be used in the present invention may be selected from the groupconsisting of bentonite, silicon dioxide, quartz, thickening agentsbased on acrylate, such as alkali-soluble or alkali-swellable emulsions,fumed silica, clay and titanate chelating agents. Exemplarily mentionedare polyvinyl alcohol (PVA), hydrophobically modified alkali solubleemulsions (HASE), hydrophobically modified ethylene oxide urethanepolymers known in the art as HEUR, and cellulosic thickeners such ashydroxymethyl cellulose (HMC), hydroxyethyl cellulose (HEC),hydrophobically-modified hydroxy ethyl cellulose (HMHEC), sodiumcarboxymethyl cellulose (SCMC), sodium carboxymethyl 2-hydroxyethylcellulose, 2-hydroxypropyl methyl cellulose, 2-hydroxyethyl methylcellulose, 2-hydroxybutyl methyl cellulose, 2-hydroxyethyl ethylcellulose, 2-hydroxypropyl cellulose, attapulgite clay, and mixturesthereof. Suitable thickening agents are commercially available products,such as Optigel WX (BYK-Chemie GmbH, Germany), Rheolate 1 (ElementisGmbH, Germany) and Acrysol ASE-60 (The Dow Chemical Company). ComponentB comprises at least about 0.01 wt.-%, preferably at least about 0.05wt.-%, more preferably at least about 0.1 wt.-%, most preferably atleast about 0.3 wt.-%, from about 0.01 wt.-% to about 15 wt.-%,preferably from about 0.05 wt.-% to about 10 wt.-%, more preferably fromabout 0.1 wt.-% to about 5 wt.-%, most preferably from about 0.3 wt.-%to about 1 wt.-% of said thickening agent, based on the total weight ofcomponent B.

The presence of a retarder and thickening agent does not change theoverall inorganic nature of the cementitious component B.

Component B comprising the initiator and retarder is present inaqueous-phase, preferably in form of a slurry or paste.

It is preferred that the pH-value of component B is above 10, morepreferably above 11 and most preferably is above 12, in particular inthe range between 10 and 14, preferably between 11 and 13.

It is particular preferred that the proportions of water in the twocomponents, namely component A and component B, are chosen so that thewater to aluminous cement ratio (W/CAC) or water to calciumsulfoaluminate cement (W/CAS), in the product obtained by mixingcomponents A and B is lower than 1.5, preferably between 0.3 and 1.2,most preferably between 0.4 and 1.0. In a preferred embodiment, theratio of water to calcium aluminate cement comprising calcium sulfate(W/(CAC+CaSO₄)) in the product obtained by mixing components A and B islower than 1.0.

Moreover, it is particular preferred that the proportion of lithium incomponent B is chosen so that the lithium to aluminous cement ratio(Li/CAC) and lithium to calcium sulfoaluminate cement (Li/CAS), in theproduct obtained by mixing components A and B is lower than 0.05,preferably between 0.001 and 0.05, most preferably between 0.005 and0.01. In a particular preferred embodiment, the proportion of lithiumhydroxide in component B is chosen so that the ratio of calciumaluminate cement comprising calcium sulfate to lithium hydroxide((CAC+CaSO4)/LiOH) in the product obtained by mixing components A and Bis in the range of from 1.3:1 to 12.5:1.

It is particular preferred that the calcium sulfate in the productobtained by mixing components A and B is present in the range of fromabout 0.95 wt.-% to 18.0 wt.-%, preferably from about 1.5 wt.-% to 14.0wt.-%, more preferably from about 2.5 wt.-% to 10.0 wt.-%, mostpreferably from about 3.0 wt.-% to 8.5 wt.-%.

Moreover, it is particular preferred that the proportion of retarder incomponent B is chosen so that the citric acid/tartaric acid to aluminouscement ratio and citric acid/tartaric acid to calcium sulfoaluminatecement, in the product obtained by mixing components A and B is lowerthan 0.5, preferably between 0.01 and 0.4, most preferably between 0.1and 0.2.

In a most preferred embodiment, component A comprises or consists of thefollowing components:

65 to 70 wt.-% of aluminous cement,

5 to 15 wt.-% calcium sulfate,

0.5 to 1.5 wt.-% of phosphoric acid,

0.5 to 1.5 wt.-% of plasticizer,

0.001 to 0.05 wt.-% of an antimicrobial or biocidal agent,

optionally 5 to 20 wt.-% of mineral fillers, and

15 to 25 wt.-% of water.

In a most preferred embodiment, component B comprises or consists of thefollowing components:

0.1 wt.-% to 4 wt.-% of lithium hydroxide,

0.1 wt.-% to 5 wt.-% of lithium sulfate or lithium sulfate monohydrate,

0.05 wt.-% to 5 wt.-% of citric acid,

0.05 wt.-% to 4 wt.-% of tartaric acid,

35 wt.-% to 45 wt.-% of a first mineral filler,

15 wt.-% to 25 wt.-% of a second mineral filler,

10 wt.-% to 20 wt.-% of a third mineral filler,

0.01 wt.-% to 0.5 wt.-% of a thickening agent, and

15 wt.-% to 25 wt.-% of water.

Component A as used in the present invention may be prepared as follows:The phosphor-containing blocking agent is mixed with water, so that thepH-value of the resulting mixture is about 2. Plasticizer is added andthe mixture homogenized. Aluminous cement, optionally calcium sulfate,and optionally mineral filler are premixed and added stepwise to themixture whilst increasing the stirring speed, so that the pH-value ofthe resulting mixture is about 4. Finally, thickening agent andantibacterial/biocidal agent are added and mixed until completehomogenization of the mixture.

Component B as used in the present invention may be prepared as follows:The accelerator is dissolved in an aqueous solution of an activator,followed by subsequent addition of retarder and homogenization of themixture. The filler(s) is/are added stepwise whilst increasing thestirring speed until the mixture homogenizes. Finally, the thickeningagent is added until complete homogenization of the mixture.

Component A and B are present in aqueous phase, preferably in form of aslurry or paste. In particular, components A and B have a pasty to fluidaspect according to their respective compositions. In one preferredembodiment, component A and component B are in paste form therebypreventing sagging at the time of mixing the two components.

The weight ratio between component A and component B (A/B) ispreferentially comprised between 7/1 and 1/3, preferably is 3/1.Preferably, the composition of the mixture comprises 75 wt.-% ofcomponent A and 25 wt.-% of component B. In an alternative embodiment,the composition of the mixture comprises 25 wt.-% of component A and 75wt.-% of component B.

The inorganic mortar system, preferably the two-component inorganicmortar system, is of mineral nature, which is not affected by thepresences of additional thickening agents of other agents.

It is preferred that the inorganic mortar system has an initial set-timeof at least 5 min, preferably of at least 10 min, more preferably of atleast 15 min, most preferably of at least 20 min, in particular in therange of from about 5 to 25 min, preferably in the range of about 10 to20 min, after mixing of the two components A and B.

In the multi-component inorganic mortar system, especially thetwo-component inorganic mortar system, the volume ratio of cementitiouscomponent A to initiator component B is 1:1 to 7:1, preferably is 3:1.In an alternative embodiment, the volume ratio of cementitious componentA to initiator component B is 1:3 to 1:2.

After being produced separately, component A and component B areintroduced into separate containers, from which they are ejected bymeans of mechanical devices and are guided through a mixing device. Theinorganic mortar system is preferably a ready-for-use system, wherebycomponent A and B are separately arranged from each other in amulti-chamber device, such as a multi-chamber cartridge and/or amulti-chamber cylinder or in two-component capsules, preferably in atwo-chamber cartridge or in two-component capsules. The multi-chambersystem preferably includes two or more foil bags for separating curablecomponent A and initiator component B. The contents of the chambers orbags which are mixed together by a mixing device, preferably via astatic mixer, can be injected into a borehole. The assembly in multiplechamber cartridges or pails or sets of buckets is also possible.

The hardening aluminous cement composition existing from the staticmixer is inserted directly into the borehole, which is requiredaccordingly for fastening the anchoring means, and has been initiallyintroduced into the mineral surface, during the chemical fastening ofanchoring means, whereupon the construction element to be fastened, forexample an anchor rod, is inserted and adjusted, whereupon the mortarcomposition sets and hardens. In particular, the inorganic mortar systemis to be considered as a chemical anchor for fastening metal elements.

Without being bound by theory, the blocking agent present in component Ainhibits the solubilization of the calcium aluminate(s) in water,thereby stopping cement hydration which leads to the curing of themixture. Upon adding the initiator component B, the pH-value is changedand the cementitious component A is unblocked and hydration reaction ofthe calcium aluminate(s) is released. As this hydration reaction iscatalyzed and accelerated by the presence of alkali metals salts, inparticular lithium salts, it has an initial set-time of shorter than 5min. In order to retard the fast curing time (initial-set time), it ispreferred that the at least one retarder comprised in component B asused in the present invention is so chosen to obtain an initial set-timeof at least 5 min, preferably of at least 10 min, more preferably of atleast 15 min, most preferably of at least 20 min, in particular in therange of from about 5 to 25 min, preferably in the range of about 10 to20 min, after mixing of the two components A and B.

The role of mineral fillers, in particular in component B, is to adjustthe final performance with regard to mechanical strength and performanceas well as long term durability. By optimizing the fillers, it ispossible to optimize the water/aluminous cement ratio which allows foran efficient and fast hydration of the aluminous cement.

The inorganic mortar system comprising the calcium sulfate can be usedfor a chemical fastening of anchoring means, preferably of metalelements, such as anchor rods, in particular threaded rods, bolts, steelreinforcement bars or the like into mineral surfaces, such as structuresmade of brickwork, concrete, pervious concrete or natural stone. Inparticular, the inorganic mortar system can be used for a chemicalfastening of anchoring means, such as metal elements, in boreholes. Ithas been found out, that the use of calcium sulfate in such an inorganicmortar system significantly increases the load values and hence loadcapacity in wet boreholes as well as in diamond drilled boreholes.

Hence, the use of calcium sulfate in an inorganic mortar systemaccording to the present invention is particular to increase loadvalues. Additionally, it is used to reduce shrinkage within theborehole.

The calcium sulfate comprised in the inorganic mortar is particularlyapplied in a method for a chemical fastening of anchoring means,preferably of metal elements, in mineral surfaces, such as structuresmade of brickwork, concrete, pervious concrete or natural stone.

Moreover, the inorganic mortar system comprising the calcium sulfate maybe used for the attachment of fibers, scrims, fabrics or composites, inparticular of high-modulus fibers, preferably of carbon fibers, inparticular for the reinforcement of building structures, for examplewalls or ceilings or floors, or further for mounting components, such asplates or blocks, e.g. made of stone, glass or plastic, on buildings orstructural elements. However, in particular it is used for fastening ofanchoring means, preferably metal elements, such as anchor rods, inparticular threaded rods, bolts, steel reinforcement bars or the likeinto recesses, such as boreholes, in mineral surfaces, such asstructures made of brickwork, concrete, pervious concrete or naturalstone, whereby the components of the two-component inorganic mortarsystem are prior mixed, for example by means of a static mixer or bydestroying a cartridge or a plastic bag, or by mixing components of amulti-chamber pails or sets of buckets.

The following example illustrates the invention without thereby limitingit.

EXAMPLES

1. Preparation of Component A and Component B

The cementitious component A as well as the initiator component B of thecomparative example 1 and 2 and of inventive examples are initiallyproduced by mixing the constituents specified in Tables 1 and 2,respectively. The proportions that are given are expressed in wt.-%.

A typical mixing protocol for component A is as follows: weighting outthe necessary quantity of water, introducing the water into a mixingbowl and slowly adding phosphoric acid thereto under stirring with adissolver plate at 150 rpm for 2 minutes; adding plasticizer andhomogenizing at 150 to 200 rpm for 2-3 minutes; premixing the aluminouscement (Ternal White®) and the respective calcium sulfate in a bigbucket and adding this mixture step by step whilst increasing thestirring speed continuously with increasing viscosity from 200 rpm to2000 rpm to avoid lump formation, after addition stirring under vacuum(150 mbar) at dissolver plate speed of 2000 rpm and bar stirrer speed of220 rpm for 5 minutes; adding slowly thickening agent and stirring atdissolver plate speed of 3000 rpm and bar stirrer speed of 220 rpm for3-5 minutes; adding antibacterial or biocidal agent and homogenizingunder vacuum (150 mbar) at dissolver plate speed of 3000 rpm and barstirrer speed of 440 rpm for 5 minutes; finally stirring under vacuum(100 mbar) at dissolver plate speed of 1500 rpm and bar stirrer speed of220 rpm for 10 minutes.

TABLE 1 Composition of component A. Comparative Example InventiveExamples Compound Function A0 A1 A2 A3 A4 A5 A6 A7 Deionized 19.80 19.8019.80 19.80 19.80 19.80 19.80 19.80 water Phosphoric blocking 0.91 0.910.91 0.91 0.91 0.91 0.91 0.91 acid 85% agent Ethacryl G plasticizer 1.171.17 1.17 1.17 1.17 1.17 1.17 1.17 Ternal aluminate 77.60 73.72 65.9663.63 58.20 54.32 50.44 42.67 White cement Micro C ettringite — 3.8811.64 13.97 19.40 23.28 27.16 34.93 former Supraduro ettringite — — — —— — — — former Lenzin ettringite — — — — — — — — former Xanthanthickening 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 Gum agent Nuosept OBbiocidal 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 03 agent InventiveExamples Compound Function A8 A9 A10 A11 A12 A13 A14 A15 Deionized water19.80 19.80 19.80 19.80 19.80 19.80 19.80 19.80 Phosphoric blocking 0.910.91 0.91 0.91 0.91 0.91 0.91 0.91 acid 85% agent Ethacryl G plasticizer1.17 1.17 1.17 1.17 1.17 1.17 1.17 1.17 Ternal White aluminate 73.7265.96 63.63 58.20 54.32 50.44 42.67 3.87 cement Micro C ettringite — — —— — — — — former Supraduro ettringite 3.88 11.64 13.97 19.40 23.28 27.1634.93 73.73 former Lenzin ettringite — — — — — — — — former Xanthanthickening 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 Gum agent Nuosept OBbiocidal 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 03 agent InventiveExamples Compound Function A16 A17 A18 A19 A20 A21 A22 Deionized water19.80 19.80 19.80 19.80 19.80 19.80 19.80 Phosphoric blocking 0.91 0.910.91 0.91 0.91 0.91 0.91 acid 85% agent Ethacryl G plasticizer 1.17 1.171.17 1.17 1.17 1.17 1.17 Ternal White aluminate 73.72 65.96 63.63 58.2054.32 50.44 42.67 cement Micro C ettringite — — — — — — — formerSupraduro ettringite — — — — — — — former Lenzin ettringite 3.88 11.6413.97 19.40 23.28 27.16 34.93 former Xanthan thickening 0.50 0.50 0.500.50 0.50 0.50 0.50 Gum agent Nuosept OB biocidal agent 0.02 0.02 0.020.02 0.02 0.02 0.02 03 Phosphoric acid 85% marketed by Sigma-AldrichChemie GmbH, Germany; Ethacryl G marketed by Coatex S.A., France; TernalWhite ® marketed by Kerneos S.A., France; Micro C (CaSO₄ anhydrite)marketed by Casea GmbH, Germany; Supraduro (CaSO₄ hemihydrate) marketedby Saint Gobain Formula GmbH, Germany; Lenzin (CaSO₄ dihydrate) marketedby Kremer Pigmente GmbH & CO. KG, Germany; Xanthan Gum marketed byKremer Pigmente GmbH & CO. KG, Germany; Nuosept OB 03 marketed byAshland Nederland B.V., The Netherlands.

A typical mixing protocol for component B is as follows: dissolvinglithium sulfate monohydrate in a 10% aqueous solution of lithiumhydroxide followed by dissolving citric acid and tartaric acid in thismixture and fully homogenizing it at 400 rpm; adding stepwise filler,starting with the roughest filler and ending with the finest one, whileincreasing stirring speed from 250 rpm to 1700 rpm and continuinghomogenizing it at 1700 rpm for 2-3 min; finally adding thickening agentwhilst stirring, and increasing stirring speed to 2200 rpm; finallycontinuing homogenizing at 2200 rpm for 5 min.

TABLE 2 Composition of component B. Compound Function B LiOH 10% (water)activator 18.68 Li₂SO₄ monohydrate accelerator 3.28 Citric acid retarder1.58 Tartaric acid retarder 0.99 Filler 1 filler 35.97¹ Filler 2 filler22.60² Filler 3 filler 16.67³ Optigel WX thickening agent 0.23 LiOH 10%(water) marketed by Bernd Kraft GmbH, Germany; Li₂SO₄ monohydratemarketed by Alfa Aesar GmbH & Co. KG, Germany; Citric acid marketed bySigma-Aldrich Chemie GmbH, Germany; Tartaric acid marketed by BCD ChemieGmbH, Germany; ¹Omyacarb 130-Al marketed by Omya International AG,Germany; ²Omyacarb 15-H Al marketed by Omya International AG, Germany;³Omyacarb 2-Al marketed by Omya International AG, Germany; Optigel WXmarketed by BYK Chemie GmbH, Germany.

2. Determination of Mechanical Performance

After being produced separately, the cementitious component A andinitiator component B are mixed in a speed mixer in a volume ratio of3:1 or 1:3 and are introduced into a prepared borehole in concreteC20/25 having a diameter of 14 or 18 mm. The borehole was created byhammer drilling.

Load values of the cured mortar composition are determined byintroducing an M12 threaded anchor rod, having an anchoring depth of 72mm, into a borehole, having a diameter of 14 or 18 mm, in differentlyconditioned concrete C20/25 (Table 3).

TABLE 3 Condition of concrete C20/25 tested. Sample number Concretecondition Borehole diameter in mm 1 dry concrete, dust completely 14,hammer drilling removed, room temperature 2 water-saturated concrete,dust 14, hammer drilling 50% removed, room temperature 3 dry concrete,dust completely 18, hammer drilling removed, room temperature

The average failure load is determined by centrally pulling out thethreaded anchor rod with tight support using high-strength steel rodsusing a hydraulic tool. Three threaded anchor rods are doweled in placein each case and their load values are determined after curing for 24hours as mean value. Ultimate failure loads are calculated as bondstrengths and given in N/mm² in Table 4.

TABLE 4 Bond strengths in N/mm². Mixing ratio Comparative A:B 1:3Example 1 Inventive Examples Example No. 1 2 3 4 5 6 7 8 Sample numberA0 + B A1 + B A2 + B A3 + B A4 + B A5 + B A6 + B A7 + B 1 6.40 6.65 6.726.66 6.52 6.20 6.24 5.37 2 7.80 8.26 8.59 8.15 8.02 7.91 7.67 6.59 35.56 5.64 5.84 5.62 5.60 5.58 5.30 4.37 Mixing ratio A:B 1:3 InventiveExamples Example No. 9 10 11 12 13 14 15 16 Sample number A8 + B A9 + BA10 + B A11 + B A12 + B A13 + B A14 + B A15 + B 1 7.70 10.11 9.50 8.567.02 6.46 4.84 0.55 2 10.55 12.33 11.85 9.28 8.55 7.33 6.05 0.32 3 6.469.88 8.64 7.65 6.93 5.31 4.06 0.20 Mixing ratio A:B 1:3 InventiveExamples Example No. 17 18 19 20 21 22 23 Sample number A16 + B A17 + BA18 + B A19 + B A20 + B A21 + B A22 + B 1 6.57 8.60 8.46 6.42 6.41 4.023.00 2 8.69 10.05 9.26 7.95 7.82 4.47 1.84 3 5.61 7.48 7.14 6.37 5.632.88 2.18 Mixing ratio Comparative A:B 3:1 Inventive Examples Example 2Example No. 24 25 26 27 28 29 Sample number A8 + B A9 + B A11 + B A12 +B A13 + B A0 + B 1 12.53 16.00 12.87 12.61 10.65 11.2

3. Determination of Chemical Shrinkage

The chemical shrinkage is determined by using the device for measuring ashrinkage “Schwindkegel Schleibinger Device” (Schleibinger GeräteTeubert and Greim GmbH, Buchbach, Germany). The sample was applied at adefined height and positioned under the laser beam on a plate instead ofa cone. An aluminum plates serving as a reflector for the laser beam.2.5 g of the sample are applied to a steel plate and covered with analuminum plate. The height of the sample is adjusted to 1.9 mm. Theshrinkage is determined by measuring the difference in length of thereflected laser-beam according to standard practice. Table 5 depicts theshrinkage compared to the initial inorganic mortar, i.e. the value −2.30means a shrinkage of 2.30% when compared to the initial material.

TABLE 5 Chemical Shrinkage. Mixing ratio Comparative A:B 1:3 ExampleInventive Examples Example No. 30 31 32 33 34 35 36 37 38 A0 + B A8 + BA9 + B A10 +B A11 +B A12 +B A13 +B A14 +B A15 +B Chemical −2.30 −1.61−1.20 −0.87 −0.74 −0.61 −0.94 −1.23 −3.06 shrinkage [%]

As it can be seen from Table 4, almost all inventive systems showconsiderable bond strengths after 24 hours of curing as well asincreased load values and hence, improved mechanical strength when itcomes to a chemical fastening of anchoring means, in comparison to thecomparative system does not comprising any calcium sulfate. The additionof calcium sulfate, in particular in a ratio of ratio of calcium sulfateto aluminous cement in a range of from 5/95 to 30/70, preferably from15/85 to 25/75, results in a significant increase of load values whencompared to systems not comprising any calcium sulfate. Moreover, it hasbeen shown that the performance improves in wet and diamond drilledboreholes. In particular, it has been shown that the addition of calciumsulfate hemihydrate results in a significant improvement of load valuesin diamond drilled boreholes (also referred to as oversize)proportionally to its shrinkage effect. Furthermore, it was found thatthe inventive systems comprising calcium sulfate do not show anymicro-cracks after curing. Hence, the inventive systems provide for adense, sealed anchoring system which is an important pre-condition forobtaining improved corrosion and freeze-thaw resistance.

As it has been shown above, the use of calcium sulfate of the presentinvention, in particular in a ratio of ratio of calcium sulfate toaluminous cement in a range of from 5/95 to 30/70, preferably from 15/85to 25/75, provides for an increase in load values and hence mechanicalstrength when compared to systems not comprising any calcium sulfate.

The invention claimed is:
 1. An inorganic mortar system for a chemicalfastening of an anchor in a mineral surface, the inorganic mortar systemcomprising: calcium sulfate, a curable aluminous cement component A, andan initiator component B for initiating a curing process, whereincomponent A comprises water, a calcium aluminate cement, at least oneplasticizer, and at least one blocking agent selected from the groupconsisting of phosphoric acid, metaphosphoric acid, phosphorous acid,and a phosphonic acid, component B comprises an initiator comprisingLiOH, at least one retarder, at least one mineral filler, and water,component A and component B are separate, a ratio of calcium aluminatecement comprising calcium sulfate to lithium hydroxide((CAC+CaSO₄)/LiOH) in the product obtained by mixing components A and Bis in the range of from 1.3:1 to 12.5:1, the calcium sulfate in theproduct obtained by mixing components A and B is present in the range offrom about 0.95 wt.-% to 18.0 wt.-% and a mortar prepared from saidinorganic mortar system has a chemical shrinkage of from −0.61 to −1.61.2. The inorganic mortar system according to claim 1, wherein component Acomprising an aqueous-phase calcium aluminate cement.
 3. The inorganicmortar system according to claim 1, wherein the calcium sulfate is inthe form of calcium sulfate anhydrite, calcium sulfate hemihydrate orcalcium sulfate dihydrate.
 4. The inorganic mortar system according toclaim 1, wherein the calcium sulfate is present in component A.
 5. Theinorganic mortar system according to claim 4, wherein the calciumsulfate is present in component A in a ratio of calcium sulfate tocalcium aluminate cement in a range of from 5/95 to 30/70.
 6. Theinorganic mortar system according to claim 1, wherein the initiatorcomprises a mixture of at least two of an alkali metal salt, an alkalineearth metal salt, and a combination thereof, the at least one retarderis selected from the group consisting of citric acid, tartaric acid,lactic acid, salicylic acid, gluconic acid, and a mixture thereof, andthe at least one mineral filler is selected from the group consisting ofa limestone filler, sand, corundum, dolomite, alkaline-resistant glass,crushed stone, gravel, pebble, and a mixture thereof.
 7. The inorganicmortar system according to claim 1, wherein the initiator comprises amixture of at least two lithium metal salts.
 8. The inorganic mortarsystem according to claim 1, wherein the ratio of water to calciumaluminate cement comprising calcium sulfate (W/(CAC+CaSO₄)) in theproduct obtained by mixing components A and B is lower than 1.0.
 9. Theinorganic mortar system according to claim 1, wherein the anchor is ananchor rod, a threaded anchor rod, a bolt, or a steel reinforcement bar.10. The inorganic mortar system according to claim 1, wherein themineral surface is a structure comprising brickwork, concrete, perviousconcrete, or natural stone.
 11. The inorganic mortar system according toclaim 1, wherein the mineral surface is a wet borehole.
 12. Theinorganic mortar system according to claim 1, wherein the mineralsurface is a diamond drilled borehole.
 13. A method of chemicalfastening of an anchor in a mineral surface, the method comprising:setting the anchor in a borehole present in the mineral surface in thepresence of the inorganic mortar system according to claim 1; and curingthe inorganic mortar system, thereby increasing a load value of theborehole filled with a cured inorganic mortar system compared to a loadvalue of a borehole without the cured inorganic mortar system.
 14. Amethod of chemical fastening of an anchor in a mineral surface, themethod comprising: setting the anchor in a borehole present in themineral surface in the presence of the inorganic mortar system accordingto claim 1; and curing the inorganic mortar system, thereby increasing aload value of the borehole filled with a cured inorganic mortar system,thereby decreasing shrinkage of a cured inorganic mortar system in theborehole compared to a load value of a borehole without the curedinorganic mortar system.
 15. The method according to claim 13, whereinthe anchor is a metal element; and the mineral surface is at least onemember selected from the group consisting of brickwork, concrete,pervious concrete, and natural stone.